This application claims the priority of German application 197 29 900.8-12, filed in Germany on Jul. 12, 1997, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a damping device for a part pivotable between two end positions, with a viscous brake for delaying pivoting movement which includes a brake wheel and a driving member engaging the wheel at a tangent.
Pivotable parts of this kind are represented in automobile construction by doors of glove compartments or other storage or receiving compartments or of auxiliary devices for user comfort that can be pivoted out for use, for example holders for drinking vessels, ashtrays, or the like.
A container of this kind such as an ashtray, storage compartment or the like that can be inserted into an installation opening in the interior of a vehicle (German Patent Document DE 195 10 749 C1) has a housing with a housing opening and a door for closing the housing opening, said door being pivotable from a closed position into an open position and vice versa. For this purpose the door is mounted laterally on two pivot arms each of which is pivotably mounted at one of two opposite side walls of the housing. The door can be locked in its closed position and is moved into its open position by an opening spring after it is unlocked. Two viscous brakes each provided on one side of the door ensure damping of the opening movement and prevent the door from forcibly striking a stop that determines its opening position. Each viscous brake has a pinion that is rotatably mounted at the two housing side walls, and an arcuate toothed segment that meshes with said pinion, said toothed segment being formed on a free end of the pivot arm that projects above the point of rotation. The two viscous brakes produce a braking torque that is constant over the pivoting path of the door, said torque ensuring a harmonic movement of the door only in conjunction with the linear spring characteristic of the opening spring. Since the spring force decreases linearly over the pivot path, it is reduced at the end of the pivot path to the point where a gentle impact of the door against the stop is ensured. In pivotable doors, for example the sealing doors of glove compartments, which move into their open position automatically under the force of gravity after being unlocked, high braking torque is a problem at the beginning of the opening movement and is not sufficiently high at the end of the opening movement to ensure that the door slides smoothly into its end position.
A goal of the invention is to produce a damping device of the species recited at the outset, equipped with economical viacous damping elements also called silicone brakes, which have a progressive damping behavior, in other words their damping action increases over the pivoting path of the part.
This goal is achieved by providing a damping device for a part pivotable between first and second end positions, with a viscous brake for delaying the pivoting movement, said brake having a brake wheel and a driving member engaging said wheel at a tangent, which brake wheel and driving member move relative to one another when the part is pivoted and as a result cause a rotation of the brake wheel, wherein one of the brake wheel and the driving member is located in a fixed location and the other on a lever that is articulated to the part, and wherein the articulation point of the lever is located on the part such that the displacement of the lever within a constant pivot angle of the part increases directly with the pivot path of the part from the first to its second end position.
The damping device according to the invention has the advantage that by introducing the lever and locating the lever articulation point on the pivoting part in the manner described, the pivoting movement of the part from its first end position takes place completely or nearly without braking action and then is increasingly braked with a braking torque that is maximal at the end. In this way, an initiation of the pivoting movement that is rapid and without delay, especially under the influence of gravity, and a sharp braking action upon reaching the second end position are both guaranteed, ensuring that the part slides gently into its end position. The change in braking torque of the viscous brake is caused by the conversion according to the invention of the constant pivoting movement segments of the part into displacement sections of the lever that constantly increase, so that assuming a constant pivoting movement of the part, the relative velocity between the braking wheel and the drive member increases and hence the rotational speed of the brake wheel increases. Since the braking torque of the viscous brake depends on the rotational speed of the brake wheel, the braking torque increases directly with the pivoting path of the part. This applies only to the pivoting movement of the part from its first into its second end position.
The introduction of the lever according to the invention also creates the possibility of transferring a stop that defines the second end position of the part from the part itself to the lever, resulting in a greater freedom of design for designing the part.
Further advantageous features of preferred embodiments of the damping device according to the invention are described herein and in the claims.
According to an advantageous feature of preferred embodiments of the invention, the drive member has associated with it a guide path that extends parallel thereto and the brake wheel is provided with a guide element located at a radial distance from its rotational axis, said element abutting the guide path, with the guide element and guide path being so located and aligned that the brake wheel and drive member are held in mutual engagement. As a result of this design measure, assurance is provided that the driving connection between the driving member and the brake wheel is maintained regardless of the movement kinematics of the lever, from the first end position of the part to the second end position.
According to an advantageous feature of preferred embodiments of the invention, a free-running or decoupling device is provided that is operable during the return pivoting movement of the part from its second into its first end position, said device eliminating the driving connection between the brake wheel and the driving member. A decoupling device of this kind allows a considerable improvement in operating comfort for the part that must be returned from its second position into its first end position by hand, since the operator does not have to perform the return movement against the braking action of the viscous brake. The mutual decoupling of the brake wheel and drive member allows an easy pivoting of the part that is perceived as pleasant, which is especially important when designing the part as the door of a glove compartment.
A free-running or decoupling device of this kind is simple to design if, according to an advantageous feature of certain preferred embodiments of the invention, a second guide path is provided for the guide element, said path running at a distance parallel to and along the first guide path such that when the guide element abuts the second guide path, the brake wheel and drive member are out of engagement. The first and second guide paths are connected at their two ends by a switch so that the guide element is forcibly switched to the respective other guide path.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.